Polymer particles which carry, implanted on their surface, amphiphilic molecules carrying ion-forming or reactive groups, a process for the preparation of these particles and their use in biological applications

Abstract

Polymer particles which carry, implanted on their surface, amphiphilic molecules carrying ion-forming or reactive groups, and dispersions thereof, which may be prepared by contacting a latex of particles of a polymer having a glass transition temperature Tg greater than about 40° C., with an amphophilic compound having an HLB greater than or equal to 10 and a molecular weight greater than or equal to 400. The contacting is carried out at a temperature within the glass transition zone of the polymer, until enmeshing of the polymer chains and of the hydrophobic blocks of the amphiphilic compound has been achieved. The hydrophilic block of the amphiphilic compound carries at least one ion-forming or reactive group. The particles and their dispersions are useful in biological applications.

We claim: 
     
       1. A process for the preparation of polymer particles comprising, implanted on their surface, molecules of an amphiphilic compound carrying ion-forming or reactive groups, said process comprising the following steps: (1) contacting a latex of particles, said particles comprising a homopolymer or a copolymer having units derived from vinylaromatic monomers, alkyl esters of alpha, beta-unsaturated acids, unsaturated esters of carboxylic acids, vinyl chloride, vinylidene chloride, dienes, or monomers having nitrile functional groups, and having a glass transition temperature Tg above about 40° C., with an amphiphilic compound having an HLB greater than or equal to 10, a molecular weight greater than or equal to 400 and comprising a hydrophobic block and a hydrophilic oligomer block, said hydrophilic oligomer block carrying at least one ion-forming or reactive group, wherein said contacting is carried out at a temperature within the glass transition zone of said homopolymer or said copolymer, until enmeshing of the polymer chains and of said hydrophobic block of said amphiphilic compound has been achieved, thereby implanting said amphiphilic compound on said particles; and   (2) isolating said particles thus obtained.   
     
     
       2. The process of claim 1, wherein said particles employed in said contacting step (1) have a diameter of from 0.01 to 50 microns, and wherein the amount of said amphiphilic compound employed is from 10 -4  to 1 mole per 100 g of said polymer. 
     
     
       3. The process of claim 1, comprising the additional step, subsequent to said contacting step (1) and prior to said isolating step (2), of removing all, or substantially all, of said amphiphilic compound which has no been fixed by implantation. 
     
     
       4. The process of claim 1, wherein said amphiphilic compound has an HLB of less than 20. 
     
     
       5. The process of claim 1, wherein said hydrophilic oligomer block comprises a polyoxyalkylene block comprising from 5 to 100 C 2  -C 3  oxyalkylene units or a hydrophilic polycarboxyethylene and/or polyamidoethylene and/or polycyanoethylene oligomer block comprising from 4 to 50 carboxyethylene and/or amidoethylene and/or cyanoethylene units, and is terminated by at least one one ion-forming or reactive group selected from the group consisting of --OH, --SO 3  H, --COOH, --CHO, --φCH 2  Cl, --NH 2 , --NR 2 , --NR 3  ⊕ (R being a C 1  -C 2  -alkyl radical), --CONH 2 , --NH--NH 2 , --NH--CO--NH--NH 2 , --SH and ##STR5## 
     
     
       6. The process of claim 1, wherein said latex of particles comprises from 1 to 50% by weight of polymer particles. 
     
     
       7. The process of claim 6, wherein said latex of particles comprises from 5 to 40% by weight of polymer particles. 
     
     
       8. The process of claim 2, wherein said particles have a diameter of from 0.01 to 15 microns. 
     
     
       9. The process of claim 1, wherein said polymer is a homopolymer or a copolymer comprising units derived from vinylaromatic monomers, alkyl esters of α,β-unsaturated acids, unsaturated esters of carboxylic acids, vinyl chloride, vinylidene chloride, dienes or monomers having nitrile functional groups. 
     
     
       10. The process of claim 1, wherein said particles of said latex are magnetizable. 
     
     
       11. The process of claim 1, wherein said contacting step (1) is carried out by introducing said amphiphilic compound into the aqueous phase of said latex at ambient temperature, and then raising the temperature to a temperature within the glass transition zone of said polymer. 
     
     
       12. Polymer particles prepared by the process of claim 1. 
     
     
       13. Polymer particles prepared by the process of claim 2.